Business cycles look universal, yet interpretations vary dramatically. Keynesians see fluctuations driven by demand shocks and insufficient spending. Monetarists focus on money supply and policy mistakes. Austrian economists emphasize credit distortions and misallocation. Real business cycle theorists point to productivity shifts and external shocks.

Each school highlights a different mechanism because cycles are multi‑causal. No single lens captures the full picture, which is why debates persist. The economy moves through overlapping waves — financial, technological, psychological — and each theory isolates one of them.